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Is the a difference in dc welders

02-10-2014, 05:24 PM

Seems like I read one time there's a difference in dc current or welds.
I have a bobcat 225 that will weld ac,dc+, and dc- . Now is there a difference in that dc current or weld than a pipeliner that only welds in dc.

I'm going to try to explain what I'm asking. A inverter power supply can be a modified wave which is cheap but not as good as a pure sine wave inverter.
Are there differences in dc welders like this maybe cheaper dc output on the lower priced welders than the higher dollar welders ?

Comment

I will attempt to answer your initial question. Yes, there is a difference between the different types of DC power and the Quality in broad terms of how well they weld. In the electric machines Transformers or Transformers with a rectifier to supply DC output will be the lower priced, and usually more bulletproof machines. They weld good enough, with the emphasis not being on the machine, but how good the welder running it is. They usually don't have all the bells and whistles in terms of features. They are great for most stick welding repairs and in harsh conditions. Inverters on the other hand are also a DC machine that uses high performance kind of electronic circuitry to take the input power and change it into clean DC welding output power. These machines can be much more small and light weight, and have almost infinite arc control adjustment dials that can fine tune the machine to get the best arc characteristics. Inverters are usually quite a bit more expensive compared to the transformer machines, they are a more compact and have the most adjustable arc and can probably be a multi process machine. where these adjustments are really nice is when TIG or Mig welding and even stick welding to do code type work with very tight parameter controls.
When you get to the engine driven side of things there are also differences. Most of the smaller miller machines are actually an alternator type machine with a rectifier section to produce the DC output welding power. This is in contrast to the Pure DC generator type machines like the SA-200 etc from the other guys, or some of the newer Miller Diesel units. The last type are the engine driven inverter or hybrid type machines . DC generators have a lot nicer arc characteristics than some of the lower end alternator/rectified types. Many guys will argue that the new inverters weld nicer than the DC Generators. Personal opinions i guess. With the newer technology the machines are fairly pricey, the older units like The DC generators have been around for a long time and are relatively simple and very bulletproof technology. If you compare a Bobcat to a BB300pro, and then to a BB350pipepro you will see a drastic difference in arc quality and characteristics and the price of the machine.

Comment

I thought that was what you were asking in terms of the SA200, It actually generates DC output welding power without any rectification. The bobcat on the other hand is really just an alternator with a rectifier to convert the AC power to DC output welding power. They both have there place, Glued lots of stuff using various bobcats over the years, they work ok but the Sa200 or any brand of pure Dc Generator type machine or the newer inverters have a much nicer and crisp arc, the SA is nice cause you can control voltage depending where you are in the taps, and the current setting dial. Some of the newer machines ( both brands ) can do this similarly by the arc control and other adjustment knobs. If you are just stick welding this can be a nice feature for certain types of work. The machines are always evolving. I have 2 TB 302 and they have a much superior arc when welding compared to the Bobcats, having the dig settings and different modes give you lots of adjustment too, without having to figure out sweet spots using the taps and current in a given range. i really like these machines. I would also like to get one of the newer Miller diesels or the lincoln Vantage series machines, they are very nice too in terms of arc quality. Im interested in trying out the Pipepro, i have heard it is similiar to the vantage 400 overall. in the shop I think that the miller inverters and the lincoln inverters are very comparible, both of them being nice to use.

I have a welding addiction

...the only stupid question is the one you didn't ask

Comment

Thanks sounds like the bobcat is kind of modified. That's what I thought. I have another thread here on a 1971 ac dc electric Lincoln idealarc would it have been the better dc weld . I welded a good bit with it today felt pretty good better than the bobcat . You got to watch how high you turn it up it runs pretty hot on the metal.